Air-brake



(No Model.)

W. W. HANSOOM.

AIR BRAKE.

Patented Sept. 22, 1885.

UNITED STATES PATENT @rricn.

WILLIAM WVALLACE HANSCOM, OF SAN FRANCISCO, CALIFORNIA.

.AlR-BRAKE.

SPECIFICATION forming part of Letters Patent No. 326,646, datedSeptemloer 22, 1885.

Application filed August 28, 1884. (No model.)

T0 610% whom it may concern-.-

Be it known that I, WILLIAM WALLACE HANSCOM, a citizen of the United States, re

' siding at the city and county of San Francisco and State of California, have invented a new and useful Improvement in Mechanism for Operating Air-Brakes on Railroads, of which the following is a specification.

My invention has for its object a more pen feet control of the train than has hitherto been attainable, and at the same time to simplify and reduce the quantity of mechanism necessary to accomplish the purpose desired, making it less subject to rapid deterioration and less liable to interruption from slight causes, therefore allowing it to be placed in the hands of those who have not had to acquire especial education for the purpose of operating it.

This brake mechanism, while always in position for operation as an automatic, is at the same time so constructed that as soon as the brakes are applied, either automatically or nonautomatieally, an additional pressure of air can be forced against the airbrake piston. to any desired degree, thus avoiding the necessity of releasing the brakes for the purpose of adding more pressure behind the pistons of the brake-cylinders or to replenish the reservoirs generally used for storing a quantity of compressed air.

I dispense with all large reservoirs for the purpose of holding compressed air in large quantities, which has to be conducted to the brakecylinders by small pipes, and compress the air as required directly in the brake-cylinders, thereby moving the least possible distance in compressing and locating the compressed air when it is to be used-that is, in the brake-cylinders themselves; and not only this, but, as in the use of large reservoirs, on the locomotives or any one particular locality, in operating the brakes, by supplying air from these reservoirs the pressure is reduced in the reservoir. In order that anecessary degree of pressure may be obtained in the brakecylinder, an excessive pressure is required to be kept up in the reservoir, especially when auxiliary reservoirs are used, and they cannot be resupplied without releasing the brakes, which,on long mountain grades, is dangerous.

By my method of operating brakes by taking the pressure directly from the air-pump that, to be able to have at command the maximum pressure which may be required, it is absolutel y necessary to carry in the large reservoirs double the pressurewhich is necessary for the proper working of the brakes, requiring not only a greater expenditure of power, but much more expensive and elaborate mechanism to prevent leakage which the higher pressu re entails.

By a reduction of pressure demanded of the air-pump a larger air-pump piston may be used, or a smaller steamcylinder, and an increased capacity is obtained. In addition, the reservoirs being dispensed with, a smaller quantity of air is required to perform the work to be done, and the airpump has more instantaneous control of the pressure.

The drawings herewith will show the construction and arrangement of the several parts so that any one skilled in the art may be enabled to construc and operate the invention.

Figure 1 represents the train-pipes, valves, and brake-cylinder as they are arranged under the bottom of the car, of which the dot ted outline A A is the plan. B is the brakecylinder, fastened to the under side of the car, and which is of such a length that the piston will not move farther than one-half the length of the cylinder during the greatest travel. 0 is the piston, with rod projecting through one end of the cylinder, and having proper packing to prevent the leakage of air, the rod being connected to the brake-levers or brakes by any suitable means required by the different arrangement of brake rods and levers in use. D is one train-pipe passing through or connected at each side of a valve, F, this valve being connected to the brakecylinder B by a short pipe. Near each end of the car the pipe D has a cock, H H, for the purpose of closing or opening either end of the pipe, as may be desired. To these cocks, at either end of the car, are connected pieces of flexible hose L L, having suitable couplings for uniting them to corresponding pipes on any other car with which the train is made up. The valve F is connected to the end, or near the end, of the cylinder B, as shown, so that the pressure of air coming through this valve may be exerted on the side of the piston opposite the piston-rod.

The cock Y, attached to the cylinder B, is

for letting out the pressure of air when desirable. E is a train pipe connected by the T-pipe G with the brake-cylinder at the opposite end from the pipe D. This pipe also has cocks I I, and flexible hose K K, and couplings similar and for a similar purpose to those on pipe D. These pipes are shown so arranged that in coupling the similar pipes of two connected or coupled cars the flexible pipes or hose will cross the center line of the car. If desired, the pipes may be so carried that the coupling pipes or hose will be at diagonally-opposite corners of each car, or at whatever point may be most convenient, according to the construction and use to be mad I of the car.

Fig. 2 is a plan showing how the connection is made between the pump N, brake-valve P, train-pipes D E, valve F, and brake-cylinder The pump N, being located at any convenient position on the locomotive or othcrwise, and the pipe R, which is the discharge pipe from the air-pump, may be ofsuch length that it will reach the valve P, which is to be placed accessible to the engineer. In this figure the flexible pipes are omitted in the train-pipes D and E between the valve Pand the brake-cylinder B for clearness in illustrating the invention and to explain the operation, it being evident that the cylinder B may be placed, on the tender or car or any other convenient or necessary location for the purpose required. M is the steam-cylinder for operating the air pump N, and will take its supply of steam fromthe usual'source in such cases. 0 is the exhaust-opening of the valve P, and may be, if desired, connected to the suction or inlet pipe of the aircylinder N by the pipe W.

Fig. 3 is an enlarged section through the valve P, showing its interior construction and the ports through which the air passes in operating the brakes. The valve S is cylindrical.and is nicely fitted to the chamber in which it oscillates. It has the ports 1 and 2,through which airis admitted from the pump Nto the train-pipes D and E, either or both,at the same time, and also to exhaust the air from either of the pipes D and E into the exhaust-port O. The dotted lines at the ports 1 and 2 show the successive positions of the valve'ports when the valve is oscillated, first, to close the port through which air may be admitted into the pipe D, and at the same time have port 2 slightly open, so that air may continue to flow into pipe E; second, when the valve is still further oscillated the valve-port opens communication between pipe D and exhaust-pipe O, by which air passes from D to O and either into the atmosphere or into the suction or inlet pipe of the air-pump N by the pipe W.

Fig. 4 is an enlarged section of the valve F,

the end, as before explained.

which is attached to the cylinderB at or near This valve consists of a chamber having three openings, to two of which, 1 and 2, the train-pipe D is connected, it forming a coupling or T for the pipe D, and serving with the opening 3 to connect it to the brake-cylinder B. Within this chamber, and having a seat so that it may open toward the brake-cylinder,is a valve, 5,for1ned of metal, and having an elastic face, 7, when it rests upon the seat. This valve is attached to the cap 11 of the chamber by four or less spring --rings,' '8 8 8, and screws 12 12 12 or their equivalent. This arrangement for supporting the valve-is shown as one of several well known to those skilled in the art, any of which may be used that is adapted to the particular conditions. This valve 5'has openings. through it, and forms the seat of a valve, 4, which opens in the opposite direction from valve 5. This valve 4 is carried by the stem 9, and is kept to its seat by the spring 10, which is made of such stiffness that the valve 4 will only open when a definite pressure has been applied'under it. The spring may be put under the valve, as shown, or on top, so that the spring may be adjusted to any tension required. The directions of the currents of air are. shown by the arrows.

A pressure-gage is placed on each .of the pipes D and E near the valve P, so that the difference in pressure in the two pipes may be noted in operating the brakes. The use of the gages is so obvious thatit is not considroe ered necessary to show them in the drawings,

but to explain their use or connection with the mechanism invented.

The operation of the mechanism is as follows, reference being had to Fig. 2: The ends of the pipes D and E beyond the brake-cylinderB being closed, the air-pump is started. and the air is compressed in the brakeoylinder and pipes D and Eequally through the ports 1 and 2 in the valve S, Fig. 3, the exhaust being open. I After a sufficient pressure is generated to. operate the brakes the valve S is turned so that the opening through port 1 into pipe D is partially closed, and if necessary so much so that a slight opening may be made between the ports D and 0, thus creating a greater pressure in the pipe E than there is in pipe D. This diiterenoein pressure, acting on the two sides of the piston G in the'brakecylinder B, will be just sufficient to keep the piston drawn backward so as to keep the brakes off the wheels. By the two gages on the pipes D and E the engineer can always,.by means of the valve S, regulate the difference in pressure to a.n icety.

To apply the brakes, the valve S is reversed in movement, so that the excess of pressure will be in pipe D, when the piston C will be forced forward by the excess of pressure on oneside, and the brakes will be applied with a I force corresponding to the difference of pressure on the two sides of the piston. It is intended thatthe springs usually applied for taking off the brakes will be a little stronger than is necessary to take them off when the air-pressure is equal on both sides of the piston, and then when a train is running and the air-pressure is equal in both pipes D and E the valve S will be in its mid-position and the communication between the pipes be free through the valve S and ports 1 and 2.

The valve 5 is to be so lightly loaded that a slight difference of pressure on the two sides will open it and allow air to pass freely through, but the valve 4 is loaded so that the pressure required to open it will be somewhat more than is required to operate or apply the brakes, so that whatever pressure may exist in pipe D will also obtain in the end of the brakecylinder, to which valve F is connected, and any decrease of pressure in pipes D and E will not reduce the pressure on that side of the piston. On the other side of the piston, the cylinder being in free communication with the pipe E, any diminution of pressure in that pipe will instantly reduce the pressure in the cylinder at this end, and the air being confined in the opposite end of the cylinder will exert its pressure in expanding and force the piston forward and apply the brakes.

The change of pressure maybe effected by the engineer moving the valve S, Fig. 3, in either direction. Should any accident occur by which either or both of the pipes D and E be broken, a loss of pressure will occur and the brakes be instantly applied by the confined air under pressure in the acting end of the brake-cylinder B.

To take off the brakes, the valve S will be moved so that the greater pressure will exist in pipe E, and the piston will be forced back.

It will be seen that, while the brakes will be applied automatically, should any accident occur so as to cause a leakage in either of the pipes D or E, yet the engineer, in applying the brakes, can exert any degree of force requisite, and that he can continue to force air through pipe Dand valve F, Fig. 2, into the brake-cylinder,should any loss of pressure occur by leakage or otherwise, without having to release the brakes for the purpose of recharging any reservoir. This is very important in going down over long grades, when the brakes have to be constantly applied, as any taking off of the brakes may allow the train to increase its speed to a dangerous extent.

Although a pipe, WV, having a cock may be used between the exhaust-opening O of the valve P and the suction opening of the airpump N, yet I prefer to use the mechanism without such pipe and cock.

Having explained my invention, what I claim, and desire to secure by Letters Patent, 1s

1. Mechanism for operating air-brakes,c0nstructed and arranged substantially as described, comprising a pump for compressing the air, a valve for distributing the air to the brake-cylinders, the valve being constructed so that the current of air may flow direct from the pump witnout the intervention of a reservoir or other obstruction into either or both ends of the brake-cylinder at the same time, two train-pipes connected to this valve and to the opposite ends of the brake-cylinder, both of these pipes permitting an unobstructed flow of air into the cylinder and an unobstructed flow from the cylinder through one of the pipes, the other pipe having a retaining pressure valve preventing the outward llow of air from the other end of the cylinder below a fixed or regulated pressure.

2. The operating-valve P, having the admission-opening R, the divided channel or passage T, the two ports for the pipes D and E, the exhaust-opening O, and the valve S, having the ports 1 and 2, so constructed that when the valve S is in or near its inid-position there will be a direct communication from the admission-opening R through the ports 1 and 2 of the valve S into the openings or ports for the pipes D and E, substantially as shown, and for the purpose described.

3. In air-brake mechanism, an air-pump, brake-valve, two lines of pipe, and brake-cylinder with its piston, in combination with a valve which will allow free admission of air to one end of the brake-cylinder and will permit the outflow when the pressure in the cylinder is above a fixed amount, substantially such as shown and described.

4. The retaining-pressure valve having the chamber F, with the openings 1 and 2 for attaching pipes, the metal valve 5, having an elastic face, 7, and held to its position on the seat by the springs 8 8 8, this valve having openings 6 6 through it, which are closed by a valve, 4, which opens in an opposite direction from valve 5, the valve 4 being loaded so that it will only be opened with a fixed pressure,substantially as shown and described.

WILLIAM WALLACE HANSCOM.

WVitn esses:

ABBIE P. HANSCOM, LILLIE F. HANSCOM. 

